Publications by authors named "Daphne Lehalle"

41 Publications

Missense and truncating variants in CHD5 in a dominant neurodevelopmental disorder with intellectual disability, behavioral disturbances, and epilepsy.

Hum Genet 2021 May 4. Epub 2021 May 4.

CHU Sainte-Justine Research Center, Montreal, QC, H3T 1C5, Canada.

Located in the critical 1p36 microdeletion region, the chromodomain helicase DNA-binding protein 5 (CHD5) gene encodes a subunit of the nucleosome remodeling and deacetylation (NuRD) complex required for neuronal development. Pathogenic variants in six of nine chromodomain (CHD) genes cause autosomal dominant neurodevelopmental disorders, while CHD5-related disorders are still unknown. Thanks to GeneMatcher and international collaborations, we assembled a cohort of 16 unrelated individuals harboring heterozygous CHD5 variants, all identified by exome sequencing. Twelve patients had de novo CHD5 variants, including ten missense and two splice site variants. Three familial cases had nonsense or missense variants segregating with speech delay, learning disabilities, and/or craniosynostosis. One patient carried a frameshift variant of unknown inheritance due to unavailability of the father. The most common clinical features included language deficits (81%), behavioral symptoms (69%), intellectual disability (64%), epilepsy (62%), and motor delay (56%). Epilepsy types were variable, with West syndrome observed in three patients, generalized tonic-clonic seizures in two, and other subtypes observed in one individual each. Our findings suggest that, in line with other CHD-related disorders, heterozygous CHD5 variants are associated with a variable neurodevelopmental syndrome that includes intellectual disability with speech delay, epilepsy, and behavioral problems as main features.
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http://dx.doi.org/10.1007/s00439-021-02283-2DOI Listing
May 2021

Impaired eIF5A function causes a Mendelian disorder that is partially rescued in model systems by spermidine.

Nat Commun 2021 02 5;12(1):833. Epub 2021 Feb 5.

Division of Evolution & Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.

The structure of proline prevents it from adopting an optimal position for rapid protein synthesis. Poly-proline-tract (PPT) associated ribosomal stalling is resolved by highly conserved eIF5A, the only protein to contain the amino acid hypusine. We show that de novo heterozygous EIF5A variants cause a disorder characterized by variable combinations of developmental delay, microcephaly, micrognathia and dysmorphism. Yeast growth assays, polysome profiling, total/hypusinated eIF5A levels and PPT-reporters studies reveal that the variants impair eIF5A function, reduce eIF5A-ribosome interactions and impair the synthesis of PPT-containing proteins. Supplementation with 1 mM spermidine partially corrects the yeast growth defects, improves the polysome profiles and restores expression of PPT reporters. In zebrafish, knockdown eif5a partly recapitulates the human phenotype that can be rescued with 1 µM spermidine supplementation. In summary, we uncover the role of eIF5A in human development and disease, demonstrate the mechanistic complexity of EIF5A-related disorder and raise possibilities for its treatment.
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http://dx.doi.org/10.1038/s41467-021-21053-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7864902PMC
February 2021

Heterozygous loss of WBP11 function causes multiple congenital defects in humans and mice.

Hum Mol Genet 2020 12;29(22):3662-3678

Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, ON M5G1X3, Canada.

The genetic causes of multiple congenital anomalies are incompletely understood. Here, we report novel heterozygous predicted loss-of-function (LoF) and predicted damaging missense variants in the WW domain binding protein 11 (WBP11) gene in seven unrelated families with a variety of overlapping congenital malformations, including cardiac, vertebral, tracheo-esophageal, renal and limb defects. WBP11 encodes a component of the spliceosome with the ability to activate pre-messenger RNA splicing. We generated a Wbp11 null allele in mouse using CRISPR-Cas9 targeting. Wbp11 homozygous null embryos die prior to E8.5, indicating that Wbp11 is essential for development. Fewer Wbp11 heterozygous null mice are found than expected due to embryonic and postnatal death. Importantly, Wbp11 heterozygous null mice are small and exhibit defects in axial skeleton, kidneys and esophagus, similar to the affected individuals, supporting the role of WBP11 haploinsufficiency in the development of congenital malformations in humans. LoF WBP11 variants should be considered as a possible cause of VACTERL association as well as isolated Klippel-Feil syndrome, renal agenesis or esophageal atresia.
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http://dx.doi.org/10.1093/hmg/ddaa258DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7823106PMC
December 2020

Next-generation sequencing in a series of 80 fetuses with complex cardiac malformations and/or heterotaxy.

Hum Mutat 2020 Dec 10;41(12):2167-2178. Epub 2020 Nov 10.

Centre de Génétique Humaine, CHU Franche-Comté, Besançon, France.

Herein, we report the screening of a large panel of genes in a series of 80 fetuses with congenital heart defects (CHDs) and/or heterotaxy and no cytogenetic anomalies. There were 49 males (61%/39%), with a family history in 28 cases (35%) and no parental consanguinity in 77 cases (96%). All fetuses had complex CHD except one who had heterotaxy and midline anomalies while 52 cases (65%) had heterotaxy in addition to CHD. Altogether, 29 cases (36%) had extracardiac and extra-heterotaxy anomalies. A pathogenic variant was found in 10/80 (12.5%) cases with a higher percentage in the heterotaxy group (8/52 cases, 15%) compared with the non-heterotaxy group (2/28 cases, 7%), and in 3 cases with extracardiac and extra-heterotaxy anomalies (3/29, 10%). The inheritance was recessive in six genes (DNAI1, GDF1, MMP21, MYH6, NEK8, and ZIC3) and dominant in two genes (SHH and TAB2). A homozygous pathogenic variant was found in three cases including only one case with known consanguinity. In conclusion, after removing fetuses with cytogenetic anomalies, next-generation sequencing discovered a causal variant in 12.5% of fetal cases with CHD and/or heterotaxy. Genetic counseling for future pregnancies was greatly improved. Surprisingly, unexpected consanguinity accounts for 20% of cases with identified pathogenic variants.
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http://dx.doi.org/10.1002/humu.24132DOI Listing
December 2020

Genotype-first in a cohort of 95 fetuses with multiple congenital abnormalities: when exome sequencing reveals unexpected fetal phenotype-genotype correlations.

J Med Genet 2020 Jul 30. Epub 2020 Jul 30.

Service d'Imagerie médicale, CHU de Besançon, Besançon, France.

Purpose: Molecular diagnosis based on singleton exome sequencing (sES) is particularly challenging in fetuses with multiple congenital abnormalities (MCA). Indeed, some studies reveal a diagnostic yield of about 20%, far lower than in live birth individuals showing developmental abnormalities (30%), suggesting that standard analyses, based on the correlation between clinical hallmarks described in postnatal syndromic presentations and genotype, may underestimate the impact of the genetic variants identified in fetal analyses.

Methods: We performed sES in 95 fetuses with MCA. Blind to phenotype, we applied a genotype-first approach consisting of combined analyses based on variants annotation and bioinformatics predictions followed by reverse phenotyping. Initially applied to OMIM-morbid genes, analyses were then extended to all genes. We complemented our approach by using reverse phenotyping, variant segregation analysis, bibliographic search and data sharing in order to establish the clinical significance of the prioritised variants.

Results: sES rapidly identified causal variant in 24/95 fetuses (25%), variants of unknown significance in OMIM genes in 8/95 fetuses (8%) and six novel candidate genes in 6/95 fetuses (6%).

Conclusions: This method, based on a genotype-first approach followed by reverse phenotyping, shed light on unexpected fetal phenotype-genotype correlations, emphasising the relevance of prenatal studies to reveal extreme clinical presentations associated with well-known Mendelian disorders.
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http://dx.doi.org/10.1136/jmedgenet-2020-106867DOI Listing
July 2020

Prenatal exome sequencing in 65 fetuses with abnormality of the corpus callosum: contribution to further diagnostic delineation.

Genet Med 2020 11 22;22(11):1887-1891. Epub 2020 Jun 22.

Service de Génétique Clinique, CHU de Dijon, Dijon, France.

Purpose: Abnormality of the corpus callosum (AbnCC) is etiologically a heterogeneous condition and the prognosis in prenatally diagnosed cases is difficult to predict. The purpose of our research was to establish the diagnostic yield using chromosomal microarray (CMA) and exome sequencing (ES) in cases with prenatally diagnosed isolated (iAbnCC) and nonisolated AbnCC (niAbnCC).

Methods: CMA and prenatal trio ES (pES) were done on 65 fetuses with iAbnCC and niAbnCC. Only pathogenic gene variants known to be associated with AbnCC and/or intellectual disability were considered.

Results: pES results were available within a median of 21.5 days (9-53 days). A pathogenic single-nucleotide variant (SNV) was identified in 12 cases (18%) and a pathogenic CNV was identified in 3 cases (4.5%). Thus, the genetic etiology was determined in 23% of cases. In all diagnosed cases, the results provided sufficient information regarding the neurodevelopmental prognosis and helped the parents to make an informed decision regarding the outcome of the pregnancy.

Conclusion: Our results show the significant diagnostic and prognostic contribution of CMA and pES in cases with prenatally diagnosed AbnCC. Further prospective cohort studies with long-term follow-up of the born children will be needed to provide accurate prenatal counseling after a negative pES result.
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http://dx.doi.org/10.1038/s41436-020-0872-8DOI Listing
November 2020

mutations in the X-linked gene cause intellectual disability with pigmentary mosaicism and storage disorder-like features.

J Med Genet 2020 12 14;57(12):808-819. Epub 2020 May 14.

Division of Genomics and Genetics, Boston Children s Hospital, Boston, Massachusetts, USA.

Introduction: Pigmentary mosaicism (PM) manifests by pigmentation anomalies along Blaschko's lines and represents a clue toward the molecular diagnosis of syndromic intellectual disability (ID). Together with new insights on the role for lysosomal signalling in embryonic stem cell differentiation, mutations in the X-linked transcription factor 3 () have recently been reported in five patients. Functional analysis suggested these mutations to result in ectopic nuclear gain of functions.

Materials And Methods: Subsequent data sharing allowed the clustering of variants identified by exome sequencing on DNA extracted from leucocytes in patients referred for syndromic ID with or without PM.

Results: We describe the detailed clinical and molecular data of 17 individuals harbouring a variant, including the patients that initially allowed reporting as a new disease-causing gene. The 12 females and 5 males presented with pigmentation anomalies on Blaschko's lines, severe ID, epilepsy, storage disorder-like features, growth retardation and recognisable facial dysmorphism. The variant was at a mosaic state in at least two male patients. All variants were missense except one splice variant. Eleven of the 13 variants were localised in exon 4, 2 in exon 3, and 3 were recurrent variants.

Conclusion: This series further delineates the specific storage disorder-like phenotype with PM ascribed to mutation in exons 3 and 4. It confirms the identification of a novel X-linked human condition associated with mosaicism and dysregulation within the mechanistic target of rapamycin (mTOR) pathway, as well as a link between lysosomal signalling and human development.
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http://dx.doi.org/10.1136/jmedgenet-2019-106508DOI Listing
December 2020

Second-tier trio exome sequencing after negative solo clinical exome sequencing: an efficient strategy to increase diagnostic yield and decipher molecular bases in undiagnosed developmental disorders.

Hum Genet 2020 Nov 12;139(11):1381-1390. Epub 2020 May 12.

UFR Des Sciences de Santé, INSERM-Université de Bourgogne UMR1231 GAD, FHU-TRANSLAD, Bâtiment B3, 15 avenue du maréchal Delattre de Tassigny, 21000, Dijon, France.

Developmental disorders (DD), characterized by malformations/dysmorphism and/or intellectual disability, affecting around 3% of worldwide population, are mostly linked to genetic anomalies. Despite clinical exome sequencing (cES) centered on genes involved in human genetic disorders, the majority of patients affected by DD remain undiagnosed after solo-cES. Trio-based strategy is expected to facilitate variant selection thanks to rapid parental segregation. We performed a second step trio-ES (not only focusing on genes involved in human disorders) analysis in 70 patients with negative results after solo-cES. All candidate variants were shared with a MatchMaking exchange system to identify additional patients carrying variants in the same genes and with similar phenotype. In 18/70 patients (26%), we confirmed causal implication of nine OMIM-morbid genes and identified nine new strong candidate genes (eight de novo and one compound heterozygous variants). These nine new candidate genes were validated through the identification of patients with similar phenotype and genotype thanks to data sharing. Moreover, 11 genes harbored variants of unknown significance in 10/70 patients (14%). In DD, a second step trio-based ES analysis appears an efficient strategy in diagnostic and translational research to identify highly candidate genes and improve diagnostic yield.
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http://dx.doi.org/10.1007/s00439-020-02178-8DOI Listing
November 2020

Further delineation of the female phenotype with KDM5C disease causing variants: 19 new individuals and review of the literature.

Clin Genet 2020 07 29;98(1):43-55. Epub 2020 May 29.

INSERM UMR1231, Equipe Génétique des Anomalies du Développement, Université de Bourgogne, Dijon, France.

X-linked intellectual disability (XLID) is a genetically heterogeneous condition involving more than 100 genes. To date, 35 pathogenic variants have been reported in the lysine specific demethylase 5C (KDM5C) gene. KDM5C variants are one of the major causes of moderate to severe XLID. Affected males present with short stature, distinctive facial features, behavioral disorders, epilepsy, and spasticity. For most of these variants, related female carriers have been reported, but phenotypic descriptions were poor. Here, we present clinical and molecular features of 19 females carrying 10 novel heterozygous variants affecting KDM5C function, including five probands with de novo variants. Four heterozygous females were asymptomatic. All affected individuals presented with learning disabilities or ID (mostly moderate), and four also had a language impairment mainly affecting expression. Behavioral disturbances were frequent, and endocrine disorders were more frequent in females. In conclusion, our findings provide evidence of the role of KDM5C in ID in females highlighting the increasing implication of XLID genes in females, even in sporadic affected individuals. Disease expression of XLID in females should be taken into consideration for genetic counseling.
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http://dx.doi.org/10.1111/cge.13755DOI Listing
July 2020

Widening of the genetic and clinical spectrum of Lamb-Shaffer syndrome, a neurodevelopmental disorder due to SOX5 haploinsufficiency.

Genet Med 2020 03 3;22(3):524-537. Epub 2019 Oct 3.

CHU de Rennes, service de génétique clinique, Rennes, France.

Purpose: Lamb-Shaffer syndrome (LAMSHF) is a neurodevelopmental disorder described in just over two dozen patients with heterozygous genetic alterations involving SOX5, a gene encoding a transcription factor regulating cell fate and differentiation in neurogenesis and other discrete developmental processes. The genetic alterations described so far are mainly microdeletions. The present study was aimed at increasing our understanding of LAMSHF, its clinical and genetic spectrum, and the pathophysiological mechanisms involved.

Methods: Clinical and genetic data were collected through GeneMatcher and clinical or genetic networks for 41 novel patients harboring various types ofSOX5 alterations. Functional consequences of selected substitutions were investigated.

Results: Microdeletions and truncating variants occurred throughout SOX5. In contrast, most missense variants clustered in the pivotal SOX-specific high-mobility-group domain. The latter variants prevented SOX5 from binding DNA and promoting transactivation in vitro, whereas missense variants located outside the high-mobility-group domain did not. Clinical manifestations and severity varied among patients. No clear genotype-phenotype correlations were found, except that missense variants outside the high-mobility-group domain were generally better tolerated.

Conclusions: This study extends the clinical and genetic spectrum associated with LAMSHF and consolidates evidence that SOX5 haploinsufficiency leads to variable degrees of intellectual disability, language delay, and other clinical features.
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http://dx.doi.org/10.1038/s41436-019-0657-0DOI Listing
March 2020

Multiplex targeted high-throughput sequencing in a series of 352 patients with congenital limb malformations.

Hum Mutat 2020 01 23;41(1):222-239. Epub 2019 Sep 23.

Service de Biochimie et Biologie Moléculaire, CHU Lille, Lille, France.

Congenital limb malformations (CLM) comprise many conditions affecting limbs and more than 150 associated genes have been reported. Due to this large heterogeneity, a high proportion of patients remains without a molecular diagnosis. In the last two decades, advances in high throughput sequencing have allowed new methodological strategies in clinical practice. Herein, we report the screening of 52 genes/regulatory sequences by multiplex high-throughput targeted sequencing, in a series of 352 patients affected with various CLM, over a 3-year period of time. Patients underwent a clinical triage by expert geneticists in CLM. A definitive diagnosis was achieved in 35.2% of patients, the yield varying considerably, depending on the phenotype. We identified 112 single nucleotide variants and 26 copy-number variations, of which 52 are novel pathogenic or likely pathogenic variants. In 6% of patients, variants of uncertain significance have been found in good candidate genes. We showed that multiplex targeted high-throughput sequencing works as an efficient and cost-effective tool in clinical practice for molecular diagnosis of congenital limb malformations. Careful clinical evaluation of patients may maximize the yield of CLM panel testing.
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http://dx.doi.org/10.1002/humu.23912DOI Listing
January 2020

A novel homozygous KCNQ3 loss-of-function variant causes non-syndromic intellectual disability and neonatal-onset pharmacodependent epilepsy.

Epilepsia Open 2019 Sep 11;4(3):464-475. Epub 2019 Aug 11.

Division of Pharmacology, Department of Neuroscience University of Naples "Federico II" Naples Italy.

Objective: Heterozygous variants in or, more rarely, genes are responsible for early-onset developmental/epileptic disorders characterized by heterogeneous clinical presentation and course, genetic transmission, and prognosis. While familial forms mostly include benign epilepsies with seizures starting in the neonatal or early-infantile period, de novo variants in or have been described in sporadic cases of early-onset encephalopathy (EOEE) with pharmacoresistant seizures, various age-related pathological EEG patterns, and moderate/severe developmental impairment. All pathogenic variants in or occur in heterozygosity. The aim of this work was to report the clinical, molecular, and functional properties of a new variant found in homozygous configuration in a 9-year-old girl with pharmacodependent neonatal-onset epilepsy and non-syndromic intellectual disability.

Methods: Exome sequencing was used for genetic investigation. KCNQ3 transcript and subunit expression in fibroblasts was analyzed with quantitative real-time PCR and Western blotting or immunofluorescence, respectively. Whole-cell patch-clamp electrophysiology was used for functional characterization of mutant subunits.

Results: A novel single-base duplication in exon 12 of (NM_004519.3:c.1599dup) was found in homozygous configuration in the proband born to consanguineous healthy parents; this frameshift variant introduced a premature termination codon (PTC), thus deleting a large part of the C-terminal region. Mutant KCNQ3 transcript and protein abundance was markedly reduced in primary fibroblasts from the proband, consistent with nonsense-mediated mRNA decay. The variant fully abolished the ability of KCNQ3 subunits to assemble into functional homomeric or heteromeric channels with KCNQ2 subunits.

Significance: The present results indicate that a homozygous loss-of-function variant is responsible for a severe phenotype characterized by neonatal-onset pharmacodependent seizures, with developmental delay and intellectual disability. They also reveal difference in genetic and pathogenetic mechanisms between - and -related epilepsies, a crucial observation for patients affected with EOEE and/or developmental disabilities.
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http://dx.doi.org/10.1002/epi4.12353DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6698674PMC
September 2019

De Novo Heterozygous POLR2A Variants Cause a Neurodevelopmental Syndrome with Profound Infantile-Onset Hypotonia.

Am J Hum Genet 2019 08 25;105(2):283-301. Epub 2019 Jul 25.

Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Oncode Institute, 3584 CT Utrecht, the Netherlands.

The RNA polymerase II complex (pol II) is responsible for transcription of all ∼21,000 human protein-encoding genes. Here, we describe sixteen individuals harboring de novo heterozygous variants in POLR2A, encoding RPB1, the largest subunit of pol II. An iterative approach combining structural evaluation and mass spectrometry analyses, the use of S. cerevisiae as a model system, and the assessment of cell viability in HeLa cells allowed us to classify eleven variants as probably disease-causing and four variants as possibly disease-causing. The significance of one variant remains unresolved. By quantification of phenotypic severity, we could distinguish mild and severe phenotypic consequences of the disease-causing variants. Missense variants expected to exert only mild structural effects led to a malfunctioning pol II enzyme, thereby inducing a dominant-negative effect on gene transcription. Intriguingly, individuals carrying these variants presented with a severe phenotype dominated by profound infantile-onset hypotonia and developmental delay. Conversely, individuals carrying variants expected to result in complete loss of function, thus reduced levels of functional pol II from the normal allele, exhibited the mildest phenotypes. We conclude that subtle variants that are central in functionally important domains of POLR2A cause a neurodevelopmental syndrome characterized by profound infantile-onset hypotonia and developmental delay through a dominant-negative effect on pol-II-mediated transcription of DNA.
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http://dx.doi.org/10.1016/j.ajhg.2019.06.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6699192PMC
August 2019

Hearing impairment as an early sign of alpha-mannosidosis in children with a mild phenotype: Report of seven new cases.

Am J Med Genet A 2019 09 26;179(9):1756-1763. Epub 2019 Jun 26.

Centre de Génétique et Centre de Référence Maladies Rares 'Anomalies du Développement' de l'Interrégion Est, Hôpital d'Enfants, CHU, Dijon, France.

Alpha-mannosidosis (AM) is a very rare (prevalence: 1/500000 births) autosomal recessive lysosomal storage disorder. It is characterized by multi-systemic involvement associated with progressive intellectual disability, hearing loss, skeletal anomalies, and coarse facial features. The spectrum is wide, from very severe and lethal to a milder phenotype that usually progresses slowly. AM is caused by a deficiency of lysosomal alpha-mannosidase. A diagnosis can be established by measuring the activity of lysosomal alpha-mannosidase in leucocytes and screening for abnormal urinary excretion of mannose-rich oligosaccharides. Genetic confirmation is obtained with the identification of MAN2B1 mutations. Enzyme replacement therapy (LAMZEDE ) was approved for use in Europe in August 2018. Here, we describe seven individuals from four families, diagnosed at 3-23 years of age, and who were referred to a clinical geneticist for etiologic exploration of syndromic hearing loss, associated with moderate learning disabilities. Exome sequencing had been used to establish the molecular diagnosis in five cases, including a two-sibling pair. In the remaining two patients, the diagnosis was obtained with screening of urinary oligosaccharides excretion and the association of deafness and hypotonia. These observations emphasize that the clinical diagnosis of AM can be challenging, and that it is likely an underdiagnosed rare cause of syndromic hearing loss. Exome sequencing can contribute significantly to the early diagnosis of these nonspecific mild phenotypes, with advantages for treatment and management.
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http://dx.doi.org/10.1002/ajmg.a.61273DOI Listing
September 2019

Increased diagnostic and new genes identification outcome using research reanalysis of singleton exome sequencing.

Eur J Hum Genet 2019 10 23;27(10):1519-1531. Epub 2019 Jun 23.

Inserm UMR 1231 GAD, Genetics of Developmental disorders, Université de Bourgogne-Franche Comté, FHU TRANSLAD, Dijon, France.

In clinical exome sequencing (cES), the American College of Medical Genetics and Genomics recommends limiting variant interpretation to established human-disease genes. The diagnostic yield of cES in intellectual disability and/or multiple congenital anomalies (ID/MCA) is currently about 30%. Though the results may seem acceptable for rare diseases, they mean that 70% of affected individuals remain genetically undiagnosed. Further analysis extended to all mutated genes in a research environment is a valuable strategy for improving diagnostic yields. This study presents the results of systematic research reanalysis of negative cES in a cohort of 313 individuals with ID/MCA. We identified 17 new genes not related to human disease, implicated 22 non-OMIM disease-causing genes recently or previously rarely related to disease, and described 1 new phenotype associated with a known gene. Twenty-six candidate genes were identified and are waiting for future recurrence. Overall, we diagnose 15% of the individuals with initial negative cES, increasing the diagnostic yield from 30% to more than 40% (or 46% if strong candidate genes are considered). This study demonstrates the power of such extended research reanalysis to increase scientific knowledge of rare diseases. These novel findings can then be applied in the field of diagnostics.
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http://dx.doi.org/10.1038/s41431-019-0442-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6777617PMC
October 2019

De novo loss-of-function KCNMA1 variants are associated with a new multiple malformation syndrome and a broad spectrum of developmental and neurological phenotypes.

Hum Mol Genet 2019 09;28(17):2937-2951

Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China.

KCNMA1 encodes the large-conductance Ca2+- and voltage-activated K+ (BK) potassium channel α-subunit, and pathogenic gain-of-function variants in this gene have been associated with a dominant form of generalized epilepsy and paroxysmal dyskinesia. Here, we genetically and functionally characterize eight novel loss-of-function (LoF) variants of KCNMA1. Genome or exome sequencing and the participation in the international Matchmaker Exchange effort allowed for the identification of novel KCNMA1 variants. Patch clamping was used to assess functionality of mutant BK channels. The KCNMA1 variants p.(Ser351Tyr), p.(Gly356Arg), p.(Gly375Arg), p.(Asn449fs) and p.(Ile663Val) abolished the BK current, whereas p.(Cys413Tyr) and p.(Pro805Leu) reduced the BK current amplitude and shifted the activation curves toward positive potentials. The p.(Asp984Asn) variant reduced the current amplitude without affecting kinetics. A phenotypic analysis of the patients carrying the recurrent p.(Gly375Arg) de novo missense LoF variant revealed a novel syndromic neurodevelopmental disorder associated with severe developmental delay, visceral and cardiac malformations, connective tissue presentations with arterial involvement, bone dysplasia and characteristic dysmorphic features. Patients with other LoF variants presented with neurological and developmental symptoms including developmental delay, intellectual disability, ataxia, axial hypotonia, cerebral atrophy and speech delay/apraxia/dysarthria. Therefore, LoF KCNMA1 variants are associated with a new syndrome characterized by a broad spectrum of neurological phenotypes and developmental disorders. LoF variants of KCNMA1 cause a new syndrome distinctly different from gain-of-function variants in the same gene.
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http://dx.doi.org/10.1093/hmg/ddz117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6735855PMC
September 2019

Secondary actionable findings identified by exome sequencing: expected impact on the organisation of care from the study of 700 consecutive tests.

Eur J Hum Genet 2019 08 24;27(8):1197-1214. Epub 2019 Apr 24.

Centre National de Recherche en Génomique Humaine, Evry, France.

With exome/genome sequencing (ES/GS) integrated into the practice of medicine, there is some potential for reporting incidental/secondary findings (IFs/SFs). The issue of IFs/SFs has been studied extensively over the last 4 years. In order to evaluate their implications in care organisation, we retrospectively evaluated, in a cohort of 700 consecutive probands, the frequency and burden of introducing the search for variants in a maximum list of 244 medically actionable genes (genes that predispose carriers to a preventable or treatable disease in childhood/adulthood and genes for genetic counselling issues). We also focused on the 59 PharmGKB class IA/IB pharmacogenetic variants. We also compared the results in different gene lists. We identified variants (likely) affecting protein function in genes for care in 26 cases (3.7%) and heterozygous variants in genes for genetic counselling in 29 cases (3.8%). Mean time for the 700 patients was about 6.3 min/patient for medically actionable genes and 1.3 min/patient for genes for genetic counselling, and a mean time of 37 min/patients for the reinterpreted variants. These results would lead to all 700 pre-test counselling sessions being longer, to 55 post-test genetic consultations and to 27 secondary specialised medical evaluations. ES also detected 42/59 pharmacogenetic variants or combinations of variants in the majority of cases. An extremely low metabolizer status in genes relevant for neurodevelopmental disorders (CYP2C9 and CYP2C19) was found in 57/700 cases. This study provides information regarding the need to anticipate the implementation of genomic medicine, notably the work overload at various steps of the process.
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http://dx.doi.org/10.1038/s41431-019-0384-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6777608PMC
August 2019

Exome sequencing in clinical settings: preferences and experiences of parents of children with rare diseases (SEQUAPRE study).

Eur J Hum Genet 2019 05 1;27(5):701-710. Epub 2019 Feb 1.

Laboratoire d'Économie de Dijon (LEDI), EA7467, University of Burgundy Franche Comté, Dijon, France.

Exome sequencing (ES) has revolutionized diagnostic procedures in medical genetics, particularly for developmental diseases. The variety and complexity of the information produced has raised issues regarding its use in a clinical setting. Of particular interest are patients' expectations regarding the information disclosed, the accompaniment provided, and the value patients place on these. To explore these issues in parents of children with developmental disorders and no diagnosis with known etiology, a multidisciplinary group of researchers from social and behavioral sciences and patient organizations conducted a mixed-methodology study (quantitative and qualitative) in two centers of expertise for rare diseases in France. The quantitative study aimed to determine the preferences of 513 parents regarding the disclosure of ES results. It showed that parents wished to have exhaustive information, including variants of unknown significance possibly linked to their child's disorder and secondary findings. This desire for information could be a strategy to maximize the chances of obtaining a diagnosis. The qualitative study aimed to understand the expectations and reactions of 57 parents interviewed just after the return of ES results. In-depth analysis showed that parents had ambivalent feelings about the findings whatever the results returned. The contrasting results from these studies raise questions about the value of the information provided and parents' high expectations regarding the results. The nature of parental expectations has emerged as an important topic in efforts to optimize accompaniment and support for families during the informed decision-making process and after disclosure of the results in an overall context of uncertainty.
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http://dx.doi.org/10.1038/s41431-018-0332-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6461801PMC
May 2019

Lysosomal Signaling Licenses Embryonic Stem Cell Differentiation via Inactivation of Tfe3.

Cell Stem Cell 2019 02 27;24(2):257-270.e8. Epub 2018 Dec 27.

Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland. Electronic address:

Self-renewal and differentiation of pluripotent murine embryonic stem cells (ESCs) is regulated by extrinsic signaling pathways. It is less clear whether cellular metabolism instructs developmental progression. In an unbiased genome-wide CRISPR/Cas9 screen, we identified components of a conserved amino-acid-sensing pathway as critical drivers of ESC differentiation. Functional analysis revealed that lysosome activity, the Ragulator protein complex, and the tumor-suppressor protein Folliculin enable the Rag GTPases C and D to bind and seclude the bHLH transcription factor Tfe3 in the cytoplasm. In contrast, ectopic nuclear Tfe3 represses specific developmental and metabolic transcriptional programs that are associated with peri-implantation development. We show differentiation-specific and non-canonical regulation of Rag GTPase in ESCs and, importantly, identify point mutations in a Tfe3 domain required for cytoplasmic inactivation as potentially causal for a human developmental disorder. Our work reveals an instructive and biomedically relevant role of metabolic signaling in licensing embryonic cell fate transitions.
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http://dx.doi.org/10.1016/j.stem.2018.11.021DOI Listing
February 2019

2.5 years' experience of GeneMatcher data-sharing: a powerful tool for identifying new genes responsible for rare diseases.

Genet Med 2019 07 19;21(7):1657-1661. Epub 2018 Dec 19.

UMR1231 GAD, Inserm-Université Bourgogne-Franche Comté, Dijon, France.

Purpose: Exome sequencing (ES) powerfully identifies the molecular bases of heterogeneous conditions such as intellectual disability and/or multiple congenital anomalies (ID/MCA). Current ES analysis, combining diagnosis analysis restricted to disease-causing genes reported in OMIM database and subsequent research investigation extended to other genes, indicated causal and candidate genes around 40% and 10%. Nonconclusive results are frequent in such ultrarare conditions that recurrence and genotype-phenotype correlations are limited. International data-sharing permits the gathering of additional patients carrying variants in the same gene to draw definitive conclusions on their implication as disease causing. Several web-based tools have been developed and grouped in Matchmaker Exchange. In this study, we report our current experience as a regional center that has implemented ES as a first-line diagnostic test since 2013, working with a research laboratory devoted to disease gene identification.

Methods: We used GeneMatcher over 2.5 years to share 71 novel candidate genes identified by ES.

Results: Matches occurred in 60/71 candidate genes allowing to confirm the implication of 39% of matched genes as causal and to rule out 6% of them.

Conclusion: The introduction of user-friendly gene-matching tools, such as GeneMatcher, appeared to be an essential step for the rapid identification of novel disease genes responsible for ID/MCA.
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http://dx.doi.org/10.1038/s41436-018-0383-zDOI Listing
July 2019

The oculoauriculofrontonasal syndrome: Further clinical characterization and additional evidence suggesting a nontraditional mode of inheritance.

Am J Med Genet A 2018 12 10;176(12):2740-2750. Epub 2018 Dec 10.

Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'Interrégion Est, Centre Hospitalier Universitaire Dijon, Dijon, France.

The oculoauriculofrontonasal syndrome (OAFNS) is a rare disorder characterized by the association of frontonasal dysplasia (widely spaced eyes, facial cleft, and nose abnormalities) and oculo-auriculo-vertebral spectrum (OAVS)-associated features, such as preauricular ear tags, ear dysplasia, mandibular asymmetry, epibulbar dermoids, eyelid coloboma, and costovertebral anomalies. The etiology is unknown so far. This work aimed to identify molecular bases for the OAFNS. Among a cohort of 130 patients with frontonasal dysplasia, accurate phenotyping identified 18 individuals with OAFNS. We describe their clinical spectrum, including the report of new features (micro/anophtalmia, cataract, thyroid agenesis, polymicrogyria, olfactory bulb hypoplasia, and mandibular cleft), and emphasize the high frequency of nasal polyps in OAFNS (56%). We report the negative results of ALX1, ALX3, and ALX4 genes sequencing and next-generation sequencing strategy performed on blood-derived DNA from respectively, four and four individuals. Exome sequencing was performed in four individuals, genome sequencing in one patient with negative exome sequencing result. Based on the data from this series and the literature, diverse hypotheses can be raised regarding the etiology of OAFNS: mosaic mutation, epigenetic anomaly, oligogenism, or nongenetic cause. In conclusion, this series represents further clinical delineation work of the rare OAFNS, and paves the way toward the identification of the causing mechanism.
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http://dx.doi.org/10.1002/ajmg.a.40662DOI Listing
December 2018

Phenotypic spectrum associated with SPECC1L pathogenic variants: new families and critical review of the nosology of Teebi, Opitz GBBB, and Baraitser-Winter syndromes.

Eur J Med Genet 2019 Dec 22;62(12):103588. Epub 2018 Nov 22.

Department of Genetics, APHP-Robert DEBRE University Hospital, Sorbonne Paris-Cité University, and INSERM UMR 1141, Paris, France. Electronic address:

The SPECC1L protein plays a role in adherens junctions involved in cell adhesion, actin cytoskeleton organization, microtubule stabilization, spindle organization and cytokinesis. It modulates PI3K-AKT signaling and controls cranial neural crest cell delamination during facial morphogenesis. SPECC1L causative variants were first identified in individuals with oblique facial clefts. Recently, causative variants in SPECC1L were reported in a pedigree reported in 1988 as atypical Opitz GBBB syndrome. Six families with SPECC1L variants have been reported thus far. We report here eight further pedigrees with SPECC1L variants, including a three-generation family, and a further individual of a previously published family. We discuss the nosology of Teebi and GBBB, and the syndromes related to SPECC1L variants. Although the phenotype of individuals with SPECC1L mutations shows overlap with Opitz syndrome in its craniofacial anomalies, the canonical laryngeal malformations and male genital anomalies are not observed. Instead, individuals with SPECCL1 variants have branchial fistulae, omphalocele, diaphragmatic hernias, and uterus didelphis. We also point to the clinical overlap of SPECC1L syndrome with mild Baraitser-Winter craniofrontofacial syndrome: they share similar dysmorphic features (wide, short nose with a large tip, cleft lip and palate, blepharoptosis, retrognathia, and craniosynostosis), although intellectual disability, neuronal migration defect, and muscular problems remain largely specific to Baraitser-Winter syndrome. In conclusion, we suggest that patients with pathogenic variants in SPECC1L should not be described as "dominant (or type 2) Opitz GBBB syndrome", and instead should be referred to as "SPECC1L syndrome" as both disorders show distinctive, non overlapping developmental anomalies beyond facial communalities.
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http://dx.doi.org/10.1016/j.ejmg.2018.11.022DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6594898PMC
December 2019

Correction: IQSEC2-related encephalopathy in males and females: a comparative study including 37 novel patients.

Genet Med 2019 Aug;21(8):1897-1898

APHP, Service de genetique medicale, Necker- Enfants Malades Hospital, Imagine Institute, Paris Descartes University, Paris, France.

This Article was originally published under Nature Research's License to Publish, but has now been made available under a CC BY 4.0 license. The PDF and HTML versions of the Article have been modified accordingly.
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http://dx.doi.org/10.1038/s41436-018-0327-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608434PMC
August 2019

IQSEC2-related encephalopathy in males and females: a comparative study including 37 novel patients.

Genet Med 2019 04 12;21(4):837-849. Epub 2018 Sep 12.

APHP, Service de genetique medicale, Necker-Enfants Malades Hospital, Imagine Institute, Paris Descartes University, Paris, France.

Purpose: Variants in IQSEC2, escaping X inactivation, cause X-linked intellectual disability with frequent epilepsy in males and females. We aimed to investigate sex-specific differences.

Methods: We collected the data of 37 unpublished patients (18 males and 19 females) with IQSEC2 pathogenic variants and 5 individuals with variants of unknown significance and reviewed published variants. We compared variant types and phenotypes in males and females and performed an analysis of IQSEC2 isoforms.

Results: IQSEC2 pathogenic variants mainly led to premature truncation and were scattered throughout the longest brain-specific isoform, encoding the synaptic IQSEC2/BRAG1 protein. Variants occurred de novo in females but were either de novo (2/3) or inherited (1/3) in males, with missense variants being predominantly inherited. Developmental delay and intellectual disability were overall more severe in males than in females. Likewise, seizures were more frequently observed and intractable, and started earlier in males than in females. No correlation was observed between the age at seizure onset and severity of intellectual disability or resistance to antiepileptic treatments.

Conclusion: This study provides a comprehensive overview of IQSEC2-related encephalopathy in males and females, and suggests that an accurate dosage of IQSEC2 at the synapse is crucial during normal brain development.
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http://dx.doi.org/10.1038/s41436-018-0268-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6752297PMC
April 2019

Clinical delineation of a subtype of frontonasal dysplasia with creased nasal ridge and upper limb anomalies: Report of six unrelated patients.

Am J Med Genet A 2017 Dec;173(12):3136-3142

Equipe GAD, INSERM LNC UMR 1231, Faculté de Médecine, Université de Bourgogne Franche-Comté, Dijon, France.

Frontonasal dysplasias are rare congenital malformations of frontonasal process-derived structures, characterized by median cleft, nasal anomalies, widely spaced eyes, and cranium bifidum occultum. Several entities of syndromic frontonasal dysplasia have been described, among which, to date, only a few have identified molecular bases. We clinically ascertained a cohort of 124 individuals referred for frontonasal dysplasia. We identified six individuals with a similar phenotype, including one discordant monozygous twin. Facial features were remarkable by nasal deformity with creased ridge and depressed or absent tip, widely spaced eyes, almond-shaped palpebral fissures, and downturned corners of the mouth. All had apparently normal psychomotor development. In addition, upper limb anomalies, frontonasal encephalocele, corpus callosum agenesis, choanal atresia, and congenital heart defect were observed. We identified five reports in the literature of patients presenting with the same phenotype. Exome sequencing was performed on DNA extracted from blood of two individuals, no candidate gene was identified. In conclusion, we report six novel simplex individuals presenting with a specific frontonasal dysplasia entity associating recognizable facial features, limb and visceral malformations, and apparently normal development. The identification of discordant monozygotic twins supports the hypothesis of a mosaic disorder. Although previous patients have been reported, this is the first series, allowing delineation of a clinical subtype of frontonasal dysplasia, paving the way toward the identification of its molecular etiology.
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http://dx.doi.org/10.1002/ajmg.a.38490DOI Listing
December 2017

Clinical whole-exome sequencing for the diagnosis of rare disorders with congenital anomalies and/or intellectual disability: substantial interest of prospective annual reanalysis.

Genet Med 2018 06 2;20(6):645-654. Epub 2017 Nov 2.

Centre de Génétique et Centre de Référence "Anomalies du Développement et Syndromes Malformatifs," Hôpital d'Enfants, Centre Hospitalier Universitaire de Dijon, Dijon, France.

PurposeCongenital anomalies and intellectual disability (CA/ID) are a major diagnostic challenge in medical genetics-50% of patients still have no molecular diagnosis after a long and stressful diagnostic "odyssey." Solo clinical whole-exome sequencing (WES) was applied in our genetics center to improve diagnosis in patients with CA/ID.MethodsThis retrospective study examined 416 consecutive tests performed over 3 years to demonstrate the effectiveness of periodically reanalyzing WES data. The raw data from each nonpositive test was reanalyzed at 12 months with the most recent pipeline and in the light of new data in the literature. The results of the reanalysis for patients enrolled in the third year are not yet available.ResultsOf the 416 patients included, data for 156 without a diagnosis were reanalyzed. We obtained 24 (15.4%) additional diagnoses: 12 through the usual diagnostic process (7 new publications, 4 initially misclassified, and 1 copy-number variant), and 12 through translational research by international data sharing. The final yield of positive results was 27.9% through a strict diagnostic approach, and 2.9% through an additional research strategy.ConclusionThis article highlights the effectiveness of periodically combining diagnostic reinterpretation of clinical WES data with translational research involving data sharing for candidate genes.
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http://dx.doi.org/10.1038/gim.2017.162DOI Listing
June 2018

Reducing diagnostic turnaround times of exome sequencing for families requiring timely diagnoses.

Eur J Med Genet 2017 Nov 12;60(11):595-604. Epub 2017 Aug 12.

Equipe Génétique des Anomalies du Développement, INSERM UMR1231, Université de Bourgogne-Franche Comté, Dijon, France; Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs, FHU TRANSLAD, Hôpital d'Enfants, CHU Dijon et Université de Bourgogne, Dijon, France. Electronic address:

Background And Objective: Whole-exome sequencing (WES) has now entered medical practice with powerful applications in the diagnosis of rare Mendelian disorders. Although the usefulness and cost-effectiveness of WES have been widely demonstrated, it is essential to reduce the diagnostic turnaround time to make WES a first-line procedure. Since 2011, the automation of laboratory procedures and advances in sequencing chemistry have made it possible to carry out diagnostic whole genome sequencing from the blood sample to molecular diagnosis of suspected genetic disorders within 50 h. Taking advantage of these advances, the main objective of the study was to improve turnaround times for sequencing results.

Methods: WES was proposed to 29 patients with severe undiagnosed disorders with developmental abnormalities and faced with medical situations requiring rapid diagnosis. Each family gave consent. The extracted DNA was sequenced on a NextSeq500 (Illumina) instrument. Data were analyzed following standard procedures. Variants were interpreted using in-house software. Each rare variant affecting protein sequences with clinical relevance was tested for familial segregation.

Results: The diagnostic rate was 45% (13/29), with a mean turnaround time of 40 days from reception of the specimen to delivery of results to the referring physician. Besides permitting genetic counseling, the rapid diagnosis for positive families led to two pre-natal diagnoses and two inclusions in clinical trials.

Conclusions: This pilot study demonstrated the feasibility of rapid diagnostic WES in our primary genetics center. It reduced the diagnostic odyssey and helped provide support to families.
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http://dx.doi.org/10.1016/j.ejmg.2017.08.011DOI Listing
November 2017

Disruption of the ATXN1-CIC complex causes a spectrum of neurobehavioral phenotypes in mice and humans.

Nat Genet 2017 Apr 13;49(4):527-536. Epub 2017 Mar 13.

GeneDx, Gaithersburg, Maryland, USA.

Gain-of-function mutations in some genes underlie neurodegenerative conditions, whereas loss-of-function mutations in the same genes have distinct phenotypes. This appears to be the case with the protein ataxin 1 (ATXN1), which forms a transcriptional repressor complex with capicua (CIC). Gain of function of the complex leads to neurodegeneration, but ATXN1-CIC is also essential for survival. We set out to understand the functions of the ATXN1-CIC complex in the developing forebrain and found that losing this complex results in hyperactivity, impaired learning and memory, and abnormal maturation and maintenance of upper-layer cortical neurons. We also found that CIC activity in the hypothalamus and medial amygdala modulates social interactions. Informed by these neurobehavioral features in mouse mutants, we identified five individuals with de novo heterozygous truncating mutations in CIC who share similar clinical features, including intellectual disability, attention deficit/hyperactivity disorder (ADHD), and autism spectrum disorder. Our study demonstrates that loss of ATXN1-CIC complexes causes a spectrum of neurobehavioral phenotypes.
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http://dx.doi.org/10.1038/ng.3808DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5374026PMC
April 2017

Intragenic FMR1 disease-causing variants: a significant mutational mechanism leading to Fragile-X syndrome.

Eur J Hum Genet 2017 04 8;25(4):423-431. Epub 2017 Feb 8.

EA 4271 GAD « Génétique des Anomalies du Développement » and FHU TRANSLAD, CHU Dijon, Université de Bourgogne, Dijon, France.

Fragile-X syndrome (FXS) is a frequent genetic form of intellectual disability (ID). The main recurrent mutagenic mechanism causing FXS is the expansion of a CGG repeat sequence in the 5'-UTR of the FMR1 gene, therefore, routinely tested in ID patients. We report here three FMR1 intragenic pathogenic variants not affecting this sequence, identified using high-throughput sequencing (HTS): a previously reported hemizygous deletion encompassing the last exon of FMR1, too small to be detected by array-CGH and inducing decreased expression of a truncated form of FMRP protein, in three brothers with ID (family 1) and two splice variants in boys with sporadic ID: a de novo variant c.990+1G>A (family 2) and a maternally inherited c.420-8A>G variant (family 3). After clinical reevaluation, the five patients presented features consistent with FXS (mean Hagerman's scores=15). We conducted a systematic review of all rare non-synonymous variants previously reported in FMR1 in ID patients and showed that six of them are convincing pathogenic variants. This study suggests that intragenic FMR1 variants, although much less frequent than CGG expansions, are a significant mutational mechanism leading to FXS and demonstrates the interest of HTS approaches to detect them in ID patients with a negative standard work-up.
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http://dx.doi.org/10.1038/ejhg.2016.204DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5386424PMC
April 2017

Molecular diagnosis of PIK3CA-related overgrowth spectrum (PROS) in 162 patients and recommendations for genetic testing.

Genet Med 2017 09 2;19(9):989-997. Epub 2017 Feb 2.

Service de Génétique, CHU de Rouen et Inserm U1079, Université de Rouen, Centre Normand de Génomique Médicale et Médecine Personnalisée, Rouen, France.

Purpose: Postzygotic activating mutations of PIK3CA cause a wide range of mosaic disorders collectively referred to as PIK3CA-related overgrowth spectrum (PROS). We describe the diagnostic yield and characteristics of PIK3CA sequencing in PROS.

Methods: We performed ultradeep next-generation sequencing (NGS) of PIK3CA in various tissues from 162 patients referred to our clinical laboratory and assessed diagnostic yield by phenotype and tissue tested.

Results: We identified disease-causing mutations in 66.7% (108/162) of patients, with mutant allele levels as low as 1%. The diagnostic rate was higher (74%) in syndromic than in isolated cases (35.5%; P = 9.03 × 10). We identified 40 different mutations and found strong oncogenic mutations more frequently in patients without brain overgrowth (50.6%) than in those with brain overgrowth (15.2%; P = 0.00055). Mutant allele levels were higher in skin and overgrown tissues than in blood and buccal samples (P = 3.9 × 10), regardless of the phenotype.

Conclusion: Our data demonstrate the value of ultradeep NGS for molecular diagnosis of PROS, highlight its substantial allelic heterogeneity, and confirm that optimal diagnosis requires fresh skin or surgical samples from affected regions. Our findings may be of value in guiding future recommendations for genetic testing in PROS and other mosaic conditions.Genet Med advance online publication 02 February 2017.
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http://dx.doi.org/10.1038/gim.2016.220DOI Listing
September 2017